A highly efficient method to access unprotected C-3 bifunctional quaternary 3-allyl-3-(amino)oxindoles

A highly efficient Rh(II) catalyzed non-radical protocol to access NH-free C-3 bifunctional oxindoles, which possess 3-allyl and 3-amino simultaneously, was first achieved by employing an intermolecular [2,3]-sigmatropic rearrangement reaction between diazooxindoles and tertiary allylic amines. Utilizing readily available allylamines as the nitrogen and allyl source concurrently, a wide range of bio-active 3-allyl-3-(amino)oxindoles were obtained in excellent yields under very mild reaction conditions; meanwhile, the TON can be up to 90 000. Our study addresses a gap in the literature by investigating intermolecular rearrangements of ammonium ylides with diazoamides, which have been relatively understudied.

Palladium catalyzed cascade umpolung allylation/acetalation for the construction of quaternary 3-amino oxindoles

Herein we reported a highly diastereoselective synthesis of quaternary 3-amino oxindoles bearing an acetal unit via a palladium catalyzed three-component cascade umpolung allylation/acetalation process. An array of 3-amino 3-allyl oxindoles incorporating diversified functional groups were prepared in good yields with exclusive diastereoselectivities. Further investigation demonstrated that the current method could also be extended to cascade umpolung allenylation/acetalation.

Allylation of isatin-derived N-Boc-hydrazones followed by Pd-catalyzed carboamination reaction: an entry to 3-spiro-pyrazolidyl-oxindoles

The indium-mediated allylation of novel 3-(2-Boc-hydrazono)indolin-2-one derivatives, followed by a palladium-catalysed carboamination reaction, is described to afford unprecedented spirocyclic oxindoles in good yields. The method provides an efficient access to both cis and trans diastereoisomers of highly functionalized compounds, bearing an N-Boc, 5-substituted pyrazolidine ring at the C3-oxindole spiro junction. The versatility of the method is fully demonstrated starting from a series of substituted isatins and employing a variety of aryl halides in the key cyclization step.

The indium-mediated allylation of novel 3-(2-Boc-hydrazono)indolin-2-one derivatives, followed by a palladium-catalysed carboamination reaction, is described to afford unprecedented spirocyclic oxindoles in good yields.

Catalytic synthesis of 3-aminooxindoles via addition to isatin imine: an update

3-Substituted-3-aminooxindoles have attracted the attention of organic chemist to develop different synthetic methodologies for their synthesis using catalysts. This review covers the recent developments.

Indium-catalysed amide allylation of α-iminoamide: highly enantioselective synthesis of amide functionalised α-methylene-γ-butyrolactams

A highly enantioselective amide allylation of α-iminoamides has been achieved using catalytic amounts of InCl₃, ZnCl₂ and a BINOL derivative.

Conformational stabilization of isatin Schiff bases – biologically active chemical probes

Two ways of conformation stabilization for isatin Schiff bases (group of biologically active compounds) are reported here: complexation with metals that stabilize E-conformer and substitution in the 4^th position of isatin core stabilizing Z-form.

Imidazolylpyridine-In(OTf)3 catalyzed enantioselective allylation of ketimines derived from isatins

An enantioselective In(OTf)₃-catalyzed allylation of ketimines derived from isatins in the presence of an imidazolylpyridine ligand is described.

Tin powder-promoted one-pot synthesis of 3-spiro-fused or 3,3′-disubstituted 2-oxindoles

A convenient and efficient method for the constructions of 3-spirooxindole derivatives or 3,3′-disubstituted oxindoles has been developed from one-pot reactions of isatins, hydrazides or aromatic amines, 2-(bromomethyl)acrylic ester in the presence of a catalytic amount of Brønsted or Lewis acid promoted by tin powder instead of toxic stannanes.